The Presence of Sterols Favors Sticholysin I-Membrane Association and Pore Formation Regardless of Their Ability to Form Laterally Segregated Domains

PEDRERA, LOHANS; GOMIDE, ANDREZA B.; SÁNCHEZ, RAFAEL E.; ROS, URIS; WILKE, NATALIA; PAZOS, FABIOLA; LANIO, MARÍA E.; ITRI, ROSANGELA; FANANI, MARÍA LAURA; ALVAREZ, CARLOS

LANGMUIR

AMER CHEMICAL SOC

Año: 2015 vol. 31 p. 9911 - 9911

0743-7463

ticholysin I (St I) is a pore-forming toxin (PFT) produced by the Caribbean Sea anemone Stichodactyla helianthus belonging to the actinoporin protein family, a unique class of eukaryotic PFT. As for actinoporins, it has been proposed that the presence of cholesterol (Chol) and the coexistence of lipid phases increase binding to the target membrane and pore-forming ability. However, little is known about the role of membrane structure and dynamics (phase state, fluidity, and the presence of lipid domains) on the activity of actinoporins or which regions of the membrane are the most favorable for protein insertion, oligomerization, and eventually pore formation. To gain insight into the role of membrane properties on the functional activity of St I, we studied its binding to monolayers and vesicles of phosphatidylcholine (PC), sphingomyelin (SM), and sterols inducing (ergosterol -Erg and cholesterol -Chol) or not (cholestenone - Cln) membrane phase segregation in liquid ordered (Lo) and